Hanoi police arrested a man Friday accused of being an accomplice in the failed heist of a gold shop which left 15 people injured one day earlier.

Ta Hai Ha, 20, from the northern province of Bac Giang was sleeping when police stormed into the house of his brother, Ta Van Thanh, in Yen Dung District, nabbing Ha at 1 a.m.

Thanh, 25, was already in custody, having been arrested for attempting to rob Hoang Tin Gold Shop on Nguyen Thai Hoc Street in Hanoi .

According to the police, at 11 a.m Thursday Thanh dropped off Ha at an intersection near the shop to act as a lookout and then entered the shop armed with a handmade bomb in a plastic bag, a knife and a taser.

He handed shop owner, Vu Hai Duong, a piece of paper that read: "I need money, give me or it (the bomb) will explode."

Duong feigned a willingness to cooperate, asking Thanh how much money he needed and then grabbed the bag and threw it out of his shop, shouting for help.

Thanh fled immediately. As some employees of the cosmetics shop next door chased him, the bomb exploded.

The blast broke the windows of a truck passing by, sending shards of glass into the face and left eye of the driver.

Fortunately for nearby pedestrians, the vehicle shielded them from the blast, possibly saving their lives.